Small laboratory animal models such as mice, rats and hamsters are widely used throughout the biomedical research community at Washington University (WU) in St. Louis and other scientific institutions. With the recent revolution in molecular biology, transgenic laboratory animal models - in particular mice - have become an indispensable part of the biomedical research armamentarium. The identification and development of methods for analyzing and evaluating the characteristics of interest within animal models remains a significant challenge. This is especially true for longitudinal studies, in which members of a sample population are followed over an extended period of time. Clearly, invasive and/or destructive procedures - especially those that require sacrifice of the subject - are incompatible with such studies. Under these circumstances, nondestructive imaging procedures, such as those offered by magnetic resonance imaging (MRI), are especially valuable. This proposal from the Biomedical Magnetic Resonance Laboratory (BMRL) at WU requests funds to purchase an 11.75 tesla small animal MRI scanner. The BMRL supports resources at the forefront of imaging science through its two 4.7T small-animal MRI scanners. However, its user base of leading scientists, representing a diverse range of biological and biophysical disciplines, has requirements that can only be met through the attributes an ultra high field scanner. The associated improvements in signal-to-noise ratio and spectral dispersion provide important advantages for small animal MRI and, in particular, for the imaging of mice. This proposal provides documentation of need, past imaging performance, organizational and training competence, and institutional commitment.